Swing mechanism for earth-moving apparatus

ABSTRACT

Swing mechanism for an earth-moving apparatus which comprises a main frame and a swing frame mounted for horizontal swinging movement about vertical pivot means on the main frame and a single double-acting hydraulic motor means. There is means on the main frame for guiding the portion of the hydraulic motor means having a cylindrical bore for rectilinear movement. A pair of elongate flexible means such as chains or cables are provided and one end of each of said flexible means is attached to the swing frame and the other end is attached to the portion of the hydraulic motor means having a cylindrical bore, whereby rectilinear movement of the portion of the hydraulic motor means having a cylindrical bore by the motor means causes the swing frame to swing about the substantially vertical pivot means.

[ June 24, 1975 Pilch SWING MECHANISM FOR Primary Examiner-Robert R. Song EARTH-MOVING APPARATUS [75] Inventor: John S. Piich, Ware, Mass. ABSTRACT Swing mechanism for an earth-moving apparatus [73] AS51811: ware Machine service ware which comprises a main frame and a swing frame Massmounted for horizontal swinging movement about ver- {22] Filed; 974 tical pivot means on the main frame and a single double-acting hydraulic motor means. There is means on [21] APPL 459320 the main frame for guiding the portion of the hydraulic motor means having a cylindrical bore for rectilin- [52] U.S. Cl 214/132; 74/892 ear movemem- A P of ekmgate flexible means such 5 r rm. cu. 3661* 9/14 as chains or cables are provided and one end of each 581 Field of Search 214 132, 138 R, 138 c, of said flexible means is attached to the swing frame 2 4/151 14 212 9 7; 74/ 92 and the other end is attached to the portion of the hydraulic motor means having a cylindrical bore. 5 References m whereby rectilinear movement of the portion of the UNITED STATES PATENTS hydraulic motor means having a cylindrical bore by the motor means causes the swing frame to swing E322 about the substantially vertical pivot means.

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SWING MECHANISM FOR EARTH-MOVING APPARATUS BACKGROUND OF THE INVENTION This invention relates to a swing mechanism for earth-moving apparatus such as backhoes, cranes, derricks or the like which include an earth-moving implement, such as a bucket or other tool associated with the remote end of a boom.

Such an apparatus commonly includes a main frame adapted to be attached to a vehicle such as a tractor, a swing frame which carries the boom and substantially vertical pivot means connecting the main frame and the swing frame for swinging movement of the swing frame about said pivot means. This permits swinging the boom to either side through a total angle of approximately 180. The swing frame mechanism is conventionally is powered by two ram type hydraulic motor means. Such an apparatus also commonly includes two elongate flexible means such as chains or cables, one having one end attached to one of the hydraulic motor means and the other end attached to the swing frame and the other having one end attached to the other bydraulic motor means and the other end attached to the swing frame. Thus, one of the motor means causes one of the elongate flexible means to rotate the swing frame means in one direction and the other motor means retains the tautness of the other elongate flexible means in the other direction and vice versa.

Such apparatus are disclosed in my U.S. Pat. No. 3,042,236 and to McLaughlin in U.S. Pat. No. 3,430,503 and Dorkins US. Pat. No. 3,250,410 (FIGS. 7 to 12). In the apparatus of each of these patents, the longitudinal axes of the hydraulic motor means extend substantially parallel to the plane of the longitudinal axis of the boom when the swing frame means is substantially at the center of its swinging movement and in the resultant apparatus, the combined length of the swing frame and the main frame when viewed from the top is relatively long and results in a poorly balanced tractor-backhoe combination. In addition, each of these patents utilizes two hydraulic motor means.

The apparatus disclosed in my U.S. Pat. No. 2,801,0l 3 also embodies two hydraulic motor means, the longitudinal axes of which extend substantially parallel to the plane of the longitudinal axis of the boom when the swing frame is substantially at the center of its swinging movement resulting in the same deficiencies stated for the above three prior patents. It also requires the use of a long chain adding to the cost of manufacture.

The apparatus disclosed in Przyblyski U.S. Pat. No. 2,655,269 utilizes two hydraulic motor means and two long cables which cross each other and pass over four sheaves so it is both expensive to manufacture and to maintain.

The apparatus of Billings U.S. Pat. No. 2,365,168 includes two hydraulic motor means and two long cables which pass over six sheaves so it is subject to the same deficiencies as the Przyblyski apparatus.

While Pitman U.S. Pat. No. 2,559,733 discloses a device wltich utilizes only one double-acting ram-type hydraulic motor means, its cables are long, they cross each other and pass over four sheaves so the apparatus is expensive to manufacture and to maintain.

SUMMARY OF THE INVENTION One object of this invention is to provide a new and improved swing mechanism for an earth-moving apparatus.

Another object is to provide such an apparatus which is economical to manufacture, to maintain and to service.

A further object is to provide such an apparatus which employs only one double-acting ram-type hydraulic motor means and which is free from sheaves associated with the elongate flexible means used to swing the swing frame means.

A still further object is to provide such a swing mechanism which is compact.

Yet another object is to provide such a swing mechanism in which the portion of the hydraulic motor means having a cylindrical bore is moved rectilinearly.

Another object is to provide a novel means on the main frame for guiding the portion of the hydraulic motor means having a cylindrical bore for rectilinear movement.

Yet a further object is to provide new and improved means for adjusting the tautness of the elongate flexible means.

Other objects and advantages of the invention will be apparent to persons skilled in the art from the following description taken in conjunction with the accompanying drawings.

In general, the swing mechanism embodying this invention comprises a main frame adapted to be carried by a vehicle, swing frame means and substantially vertical pivot means connecting the main frame and the swing frame means for swinging movement of the swing frame means about the vertical pivot means. The mechanism also comprises one double-acting ram-type hydraulic motor means. There are means on the main frame for guiding the portion of the hydraulic motor means having a cylindrical bore for rectilinear movement. There are a pair of elongate flexible means such as chains or cables, one end of each being attached to the swing frame means and the other end being attached to the portion of the hydraulic motor means having a cylindrical bore, whereby rectilinear movement of the portion of the hydraulic motor means having a cylindrical bore by the motor means causes the swing frame to swing about the substantially vertical pivot means and longitudinal movement of both of said elongate flexible means.

The swing mechanism also comprises a boom having one end pivotally attached to the swing frame for movement about a horizontal axis permitting movement of the boom in a substantially vertical plane and the means for guiding the portion of hydraulic motor means having a cylindrical bore during its rectilinear movement are constructed so that such movement is in a direction which is substantially normal to the longitudinal centerline of the boom when the swing frame is substantially at the center of its swinging movement and the apparatus is viewed from the top.

Preferably the portion of the hydraulic motor means having a cylindrical bore is so positioned that when the swing frame is substantially at the center of its swinging movement, opposite portions of the portion of the hydraulic motor means having a cylindrical bore extend to opposite sides of a plane through the longitudinal centerline of the boom and the portions of the elongate flexible means are substantially normal to that plane so that a short main frame may be utilized, thus resulting in a better balanced backhoe-tractor combination.

According to a preferred embodiment, the swing frame means comprises a generally cylindrical member which is substantially coaxial with the vertical pivot means and, when the swing frame is substantially at the center of its swing and the apparatus is viewed from the top, each of the elongate flexible means passes around an arcuate peripheral face of the generally cylindrical member across a plane through the longitudinal centerline of the boom which is substantially normal to the portion of the hydraulic motor means having a cylindrical bore and thence substantially parallel to the longitudinal centerline of the portion of the hydraulic motor means having a cylindrical bore to the locality of attachment of its ends thereto, whereby short elongate flexible means may be utilized.

Accordingly, during each unit of rectilinear move ment of the movable member, a substantially equal unit of one of the elongate flexible means is unwound from the arcuate surface of the generally cylindrical member and a substantially equal unit of the other of the elongate flexible means is wound upon the arcuate surface of the generally cylindrical member.

In a preferred embodiment, the portion of the hydraulic motor means having a cylindrical bore com prises means for adjusting the tautness of at least one of the elongate flexible means which is attached thereto.

In a preferred embodiment, the apparatus comprises means on the swing frame associated with one end of at least one of the elongate flexible means for adjusting the tautness of that flexible means.

In a preferred embodiment. the generally cylindrical member of the swing frame is mounted to provide a gap between the longitudinally extending side of the portion of the hydraulic motor means having a cylindrical bore and the adjacent portion of the arcuate face of the generally cylindrical member the width of which is only slightly greater than the thickness of the elongate flexible means when viewed from the top. Portions of the pair of elongate flexible means are located in that gap during all rectilinear movements of the portion of the hydraulic motor means having a cylindrical bore so that the distance between the axis of the generally cylindrical member and the face of the portion of the hydraulic motor means having a cylindrical bore is reduced to provide a compact device when viewed from the top.

in a preferred embodiment, one end of the first elongate flexible means is attached adjacent to one end of the portion of the hydraulic motor means having a cylindrical bore and the other end of the first elongate flexible means is attached to a side of the swing frame which is remote from that end of the portion of the hydraulic motor means having a cylindrical bore. One end of the second elongate flexible means is attached to the other end of the portion of the hydraulic motor means having a cylindrical bore and the other end of the second elongate flexible means is attached to the opposite side of the swing frame whereby the lengths of the flexible means are reduced and the swing frame is swung in a direction opposite to the direction of rectilinear movement of the portion of the hydraulic motor means having a cylindrical bore when viewed from the top.

In a preferred embodiment, the pair of elongate flexible means are attached to the portion of the hydraulic motor means having a cylindrical bore so that their longitudinal centerlines extend in substantially parallel planes which are substantially parallel to the longitudinal centerline of the portion of the hydraulic motor means having a cylindrical bore when viewed from the front and the longitudinal centerlines of the elongate flexible means remain in such spaced planes throughout all swinging movements of the swing frame means.

The apparatus is free from sheaves for coaction with the elongate flexible means.

The guide means on the portion of the hydraulic motor means having a cylindrical bore coact with guide means on the main frame to prevent or limit axial movements of the portion of the hydraulic motor means having a cylindrical bore.

In a preferred embodiment, the rod portion of the ram of the hydraulic motor means comprises means for adjusting the spacing between at least one end of the rod and the main frame.

In the preferred embodiment, one end of the first elongate flexible means is attached to a first locality of the portion of the hydraulic motor means having a cylindrical bore and one end of the second elongate flexible means is attached to a second locality of the portion of the hydraulic motor means having a cylindrical bore which is spaced from said first locality and both of those localities of attachment are located between the longitudinal centerline of the portion of the hydraulic motor means having a cylindrical bore and a plane through the axis of said vertical pivot means which is substantially normal to the longitudinal centerline of the boom when the apparatus is viewed from the top and the swing frame means is substantially at the center of its swing, whereby the axial and lineal loads of the flexible means are taken by the means for guiding the portion of the hydraulic motor means having a cylindrical bore. in this embodiment, preferably the other end of the first elongate flexible means is attached to a first locality of the swing frame means and the other end of the second elongate flexible means is attached to a second locality of the swing frame means which is spaced from the locality of attachment of the other end of the first elongate flexible means to the swing frame means, whereby rectilinear movement of the portion of the hydraulic motor means having a cylindrical bore in one direction causes one of the elongate flexible means to rotate the swing frame means in one direction and retains the tautness of the other elongate flexible means in the other direction and the tautness of each of the flexible means is thereby maintained at all times.

In a preferred embodiment, one end of the first elongate flexible means is attached at a first point adjacent to one end of the portion of the hydraulic motor means having a cylindrical bore and one end of the second elongate flexible means is attached to a second point adjacent to the other end of the portion of the hydraulic motor means having a cylindrical bore and the distance between the first point and the axis of the vertical pivot means is greater than the distance between the second point and the axis of the vertical pivot means when the swing frame means and boom have been swung to the full extent of their swing in one direction.

Preferably, the swing frame means comprises a generally cylindrical member which is substantially coaxial with the vertical pivot means and, when the swing frame means is substantially at the center of its swing and the apparatus is viewed from the top, each of the elongate flexible means passes around an arcuate peripheral face of the generally cylindrical member across a plane through the longitudinal centerline of the boom which is substantially normal to the portion of the hydraulic motor means having a cylindrical bore, whereby when the swing frame and boom have been swung to the full extent of their swing in one direction. the portion of one elongate flexible means which engages the arcuate peripheral face of the generally cylindrical member is greater than the length of the remainder of that elongate flexible means.

A swing frame mechanism embodying this invention utilizes only one double-acting ram-type motor means, is free from sheaves associated with the elongate flexible means. is economical to manufacture, service and maintain, is compact, includes means for adjusting the tautness of the elongate flexible means and otherwise fulfills or satisfies the above stated objects and advantages.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a top plan view showing a swing mechanism for an earth-moving apparatus embodying this invention with parts of the main frame broken away;

FIG. 2 is a front elevation of the apparatus shown in FIGv 1;

FIG. 3 is an end view taken on the line 3-3 of FIG. 2;

FIG. 4 is a section taken on the line 4-4 of FIG. 3;

FIG. 5 is a section taken on the line 55 of FIG. 4;

FIG. 6 is a top plan view of the apparatus of FIG. 1 but with the swing frame means swung substantially 90 from its position in FIGS. 1 to 5;

FIG. 7 is a diagrammatic plan view showing the attachment of one end of the upper elongate flexible means to the swing frame means and the attachment of its other end to means for adjusting its tautness located on the portion of the hydraulic motor means having a cylindrical bore; and

FIG. 8 is a diagrammatic plan view similar to FIG. 7 but showing the attachment of the end of the lower elongate flexible means to means for adjusting its tautness located on the swing frame means and the attachment of its other end to a portion of the hydraulic motor means having a cylindrical bore.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now more particularly to the drawings, wherein similar reference characters designate corresponding parts throughout, the invention relates to a swing mechanism for earth-moving apparatus such as backhoes, cranes, derricks and the like which include an earth-moving implement such as a bucket or other tool associated with the remote end of a boom.

The swing mechanism of the present invention is shown applied to a backhoe having a main frame 10 which may be permanently built onto the rear of an industrial type tractor or may be a separate unit adapted to be attached thereto. In the embodiment shown in the drawings, the main frame 10 is a separate unit the ends 13 of which are provided with a pair of orifices 11 and a pair of semicircular grooves 12 (FIG. 3) adapted to receive bolts for securing the main frame to the rear of a tractor. The main frame also includes top and bottom members 23 and 24 and a rear member 33 attached between the ends 13 as by welding.

The main frame is provided with conventional stabilizer legs 15 projecting laterally from each side thereof which are forced by the double-acting ram-type hydraulic motor means 16 into contact with the ground when the backhoe is being used. Only the rods of the rams of these hydraulic motor means and segments of the stabilizer legs are shown in the drawings since such hydraulic motor means and stabilizers are well known in the art.

A swing frame 18 is pivotally mounted on the main frame by a pair of vertically extending pivots 20-20 which pass through the elements 21 of the swing frame and the outwardly extending projections 22 which are secured to upper and lower members 23, 24 of the main frame (FIG. 2).

The horizontal pivot pin 26 which passes through the sides 18A of the swing frame and the ends of the backhoe boom 25 support the boom for vertical swinging movement. A double-acting ram-type hydraulic motor means 27 is pivotally connected between the sides 18A of the swing frame by the horizontal pivot pin 28 (FIGS. 1 and 6). Only the rod portion of the ram of this hydraulic motor means is shown in the drawings because such motor means are well known in the art for use in swinging a boom about a horizontal pivot. A bucket or other earth-moving tool (not shown) is attached to a dipperstick (not shown) which in turn is attached to the end of the boom by conventional means (not shown).

The double-acting ram-type hydraulic motor means comprises a portion indicated generally by the numeral 30 having a cylindrical bore which includes two pair of end members 31, 32. The end members 32 are attached as by welding to the ends of the cylinder 34. The end members 31 are attached to the end members 32 by the bolts 31A.

A member 32A projects forwardly from one end member 32 as shown in FIGS. 4 and 5. The member 36 is provided with a pair of elongate slots 38 and it is attached to the end member 32 by a pair of bolts 37 which pass through the elongate slots into the end member. The member 36 has a downwardly extending projection 36A and the bolt 39 passes through an interiorly threaded passage therein with its end bearing against the member 32A. By adjustment of the bolt 39, the element 36 may be slid longitudinally with respect to the element 32A for a reason which will be described below.

The rod 34A of the double-acting ram-type hydraulic motor means has its left hand end positioned against the end of the adjusting bolt 408 which is threaded through the end member 13 and the lock nut 40C holds the bolt and rod in adjusted position. The other end of the rod is positioned against the other main frame end member 13 by the bolt 40 and nut 40A (FIG. 2) so that the spacing of that end of the rod may be adjusted relative to the adjacent end member 13.

A pair of elongate guide strips 41 are attached to the end members 32 (FIGS. 1 and 4) and they coact with the elongate guide members 42 which are secured to the main frame to guide the portion having a cylindrical bore 30 for rectilinear movement substantially parallel to the longitudinal axis of the hydraulic motor means.

The boom 25 attached to the swing frame means can be swung about the vertical pivots 20 through an arc of substantially I to positions where it is substantially parallel to the face of the main frame, one such position being shown in FIG. I. At the center of such swinging movement. it is in the position shown in FIG. 6.

The piston 34B (FIGS. 1 and 6) of the hydraulic motor means is secured to the rod 34A. Oil or other fluid under pressure is supplied through hoses (not shown) from a source of fluid under pressure (not shown) through the connections 45 (FIGS. 1 and 6) to the interior of the portion having a cylindrical bore. This oil acting against the piston 348 causes the portion having a cylindrical bore to be moved rectilinearly with respect to the main frame. for example from the position of FIG. 1 to the position of FIG. 6, and this rectilinear movement is substantially normal to a plane through the longitudinal centerline of the boom when the swing frame is substantially at the center of its swinging movement and is viewed from the top (FIG. 6).

The swinging movement of the swing frame about the vertical pivots is caused by a pair of elongate flexible means such as a pair of chains 50 and 51. While chains are shown in the drawings. cables or other elongate flexible means may be used.

A generally cylindrical member 55 is secured to the swing frame with its axis substantially coaxial with the vertical pivot 20. It is mounted so that the gap between the portion having a cylindrical bore and the adjacent arcuate face of the generally cylindrical member is only slightly greater than the thickness of each chain when viewed from the top thereby to provide a compact device.

One end of the upper chain 50 is attached to the surface of the generally cylindrical member 55 by a lug 50A and a pin 50B (FIGS. 6 and 7). The other end of this chain is attached to the adjustable member 36 by the lug 50C and the pin 50D. Thus the tautness of the chain 50 may be adjusted by loosening the screws 37 and adjustment of the bolt 39 (FIG. 4) which causes the adjustable member 36 to slide longitudinally.

The lower chain 51 has one end attached to the swing frame by a bolt 51A which passes through a boss 55A secured between one of the side members 18A of the swing frame and the generally cylindrical member 55 and has its end secured to the end of the chain 51 (FIGS. 6 and 8). The other end of the lower chain 51 is attached to the lug 518 which is integral with with the left hand end member 32, the end of the chain being secured thereto by a pin 51C (FIGS. 1, 6 and 8). The tautness of the lower chain may be adjusted by adjustment of the bolt 51A.

Thus it will be observed that one end of each chain is attached to the swing frame means and the other end is attached to the portion having a cylindrical bore and, consequently, when the portion having a cylindrical bore is moved rectilinearly in one direction by admission of oil under pressure into one end of the portion having a cylindrical bore. the portion having a cylindrical bore moves rectilinearly in one direction and thereby causes the swing frame to turn in one direction and when the oil is admitted to the opposite end of the portion having a cylindrical bore, the portion having a cylindrical bore is moved in the opposite direction causing the swing frame to be swung in the opposite direction. The amount of swing in either direction may be controlled by the operator who is provided with a control valve for directing the hydraulic fluid through hoses into one or the other of the inlets 45 which pass through the end members 31.

It will be observed from FIG. 2 that the longitudinal distance between the longitudinal centerlines of the chains and 51 when viewed from the front is greater than the height of one of the chains.

It will also be observed that each of the chains is very short because each chain has one end attached near the end of a longitudinal side of the portion having a cylindrical bore and its other end attached to the swing frame 18 at a locality such that when the swing frame is at one end of its swing, as in FIG. 1, the swing frame is positioned so that one end of the chain 51 is almost adjacent the opposite end of the portion having a cylindrical bore. The same is true of the other chain 50 when the swing frame is at the end of its swing in the opposite direction.

It will also be observed that the longitudinal center line of at least one of the chains is in a different plane from the plane of the longitudinal centerline of the portion having a cylindrical bore 30 when viewed from the front as in FIG. 2 and that the longitudinal centerlines of the chains are in spaced substantially horizontal planes and remain in such planes throughout all swinging movements of the swing frame.

The apparatus is free from any sheaves for coaction with the chains thus saving cost of construction.

When the swing frame is substantially at the center of its swing and the apparatus is viewed from the top, as in FIG. 6, each of the chains pass around an arcuate peripheral face of the substantially cylindrical member 55 and across a plane through the longitudinal centerline of the boom substantially normal to the longitudinal centerline of the portion having a cylindrical bore and thence substantially parallel to the longitudinal centerline of the portion having a cylindrical bore to the locality of the attachment of the end of the chain to the portion having a cylindrical bore. so that during each unit of rectilinear movement of the movable member, a substantially equal unit of one of the chains is unwound from the arcuate face of the generally cylindrical member 55 and a substantially equal unit of the other chain is wound about said arcuate face.

It will also be observed from FIG. 6 that the portion having a cylindrical bore is so positioned that when the swing frame means is substantially at the center of its swinging movement and the apparatus is viewed from the top operative portions of the portion having a cylindrical bore extend to opposite sides of a plane through the longitudinal centerline of the boom substantially normal to the longitudinal centerline of the portion having a cylindrical bore and that portions of the chains are substantially normal to that plane whereby short chains may be used.

As shown in FIG. 2, the pair of chains are attached to the swing frame so that they extend in spaced substantially parallel planes.

It will also be observed that the guide strips 41 on the portion having a cylindrical bore are positioned at external portions of the portion having a cylindrical bore so that axial movements of the movable member are limited.

It will also be observed that one end of a first elongate flexible means 50 is attached to a first locality 50C of the portion 30 having a cylindrical bore and one end of the second elongate flexible means 51 is attached to a second locality 51B of the portion having a cylindrical bore which is spaced from the first locality and both of these localities of attachment are located between the longitudinal centerline of the portion having a cylindrical bore and a plane through the axis of the vertical pivot means which is substantially normal to the longitudinal centerline of the boom when the apparatus is viewed from the top and the swing frame means is substantially at the center of its swing as shown in FIG. 6, so that the axial and lineal loads of the flexible means are taken by the means 41 and 42 for guiding the portion having a cylindrical bore,

In addition, the other end of the first elongate flexible means 50 is attached to a first locality 50A of the swing frame means 18 and the other end of the second elongate flexible means 51 is attached to a second locality 55A of the swing frame which is spaced from the locality 50A of attachment of said other end of said first elongate flexible means to the swing frame means, so that rectilinear movement of the portion having a cylin drical bore in one direction causes one of the elongate flexible means to rotate the swing frame means in one direction and retains the tautness of the other elongate flexible means in the other direction and the tautness of each of the flexible means is thereby maintained at all times.

Furthermore, one end of the first elongate flexible means 50 is attached at a first point 50D adjacent to one end of the portion having a cylindrical bore and one end of the second elongate flexible means 51 is attached to a second point 51C adjacent to the other end of the portion having a cylindrical bore and the distance between the first point 50D and the axis of the vertical pivot means 20 is greater than the distance be tween the second point 51C and the axis of the vertical pivot means when the swing frame means and boom have been swung to the full extent of their swing in one direction as shown in FIG. 1.

Furthermore, when the swing frame means is substantially at the center of its swing and the apparatus is viewed from the top as shown in FIG. 6, each of the elongate flexible means passes around an arcuate peripheral face of the generally cylindrical member 55 across a plane through the longitudinal centerline of the boom which is substantially normal to the portion having a cylindrical bore so that when the swing frame and boom have been swung to the full extent of their swing in one direction as shown in FIG. 1, the portion of the elongate flexible means 50 which engages the arcuate peripheral face is greater than the length of the remainder of that elongate flexible means. The same is true of the elongate flexible means 51 when the swing frame and boom have been swung to the full extent in the opposite direction.

A swing frame mechanism embodying this invention utilizes only one double-acting ram-type motor means, is free from sheaves associated with the elongate flexi ble means, is economical to manufacture, service and maintain, is compact, includes means for adjusting the tautness of the elongate flexible means and otherwise fulfills all of the above stated objects and advantages.

While one desirable embodiment of the invention has been shown and described, it is to be understood that this disclosure is for the purpose ofillustration only and that various changes in shape, proportion and arrangement of parts as well as the substitution of equivalent elements for those herein shown and described may be made without departing from the spirit and scope of the invention as set forth in the appended claims.

I claim:

1. In swing mechanism for an earth-moving apparatus comprising.

a main frame adapted to be carried by a vehicle.

swing frame means. and

substantially vertical pivot means connecting said main frame and said swing frame means for swinging movement of said swing frame means about said substantially vertical pivot means.

the improvement comprising,

a single, double-acting ram-type hydraulic motor means, comprising a portion having a cylindrical bore and a piston rod having at least one end supported by at least one laterally spaced member of said main frame,

a pair of elongate flexible means, one end of each of said flexible means being attached to said swing frame means. the other end of one of said flexible means being attached to said portion having a cylindrical bore adjacent to one end thereof and the other end of the other of said flexible means being attached to said portion having a cylindrical bore adjacent to the end thereof.

means on the main frame and on said portion having a cylindrical bore for guiding said portion having a cylindrical bore and at least portions of said flexible means for rectilinear movement, and

said swing mechanism being free from any sheaves for coaction with said elongate flexible means,

whereby rectilinear movement of said portion having a cylindrical bore by said motor means causes said swing frame means to swing about said substantially vertical pivot means and longitudinal movement of both of said elongate flexible means.

2. Apparatus according to claim 1 which also comprises boom means having one end pivotally attached to said swing frame means permitting movement of said boom in a substantially vertical plane and wherein said means for guiding said portion having a cylindrical bore guides its rectilinear movement in a direction which is substantially normal to the longitudinal centerline of the boom when the swing frame means is substantially at the center of its substantially horizontal swinging movement and the apparatus is viewed from the top.

3. Apparatus according to claim 2 wherein said swing frame means comprises a generally cylindrical member which is substantially coaxial with said vertical pivot means, and when said swing frame means is substantially at the center of its swing and the apparatus is viewed from the top, each of said elongate flexible means passes around an arcuate peripheral face of the generally cylindrical member across a plane through the longitudinal centerline of the boom which is substantially normal to the longitudinal centerline of said portion having a cylindrical bore, and thence substantially parallel to said latter longitudinal centerline to the locality of attachment of its ends to said portion having a cylindrical bore, whereby during each unit of rectilinear movement of said portion having a cylindrical bore, a substantially equal unit of one of said elongate flexible means is unwound from the generally cylindrical member and a substantially equal unit of the other of said elongate flexible means is wound upon the generally cylindrical member.

4. Apparatus according to claim 2 wherein one end of the first elongate flexible means is attached to a first locality of said portion having a cylindrical bore and one end of the second elongate flexible means is attached to a second locality of said portion having a cylindrical bore which is spaced from said first locality and both said localities of attachment are located between the longitudinal centerline of said portion having a cylindrical bore and a plane through the axis of said vertical pivot means which is substantially normal to the longitudinal centerline of the boom when the apparatus is viewed from the top and thw swing frame means is substantially at the center of its swing. whereby axial and lineal loads of the flexible means are taken by said means for guiding said portion having a cylindrical bore.

5. Apparatus according to claim 2 wherein said swing frame means comprises a generally cylindrical member which is substantially coaxial with said vertical pivot means, and when said swing frame means is substantially at the center of its swing and the apparatus is viewed from the top, each of said elongate flexible means passes around an arcuate peripheral face of the generally cylindrical member across a plane through the longitudinal centerline of the boom which is substantially normal to the longitudinal centerline of said portion having a cylindrical bore, whereby when the swing frame and boom have been swung to the full ex tent of their swing in one direction, the portion of one elongate flexible means which engages said arcuate peripheral face is greater than the length of the remainder of said one elongate flexible means.

6. Apparatus according to claim 1 wherein one end of the first elongate flexible means is attached to a first locality of said portion having a cylindrical bore and one end of the second elongate flexible means is attached to a second locality of said portion having a cylindrical bore which is spaced from said first locality, the other end of said first elongate flexible means being attached to a first locality of said swing frame means and the other end of said second elongate flexible means being attached to a second locality of said swing frame means which is spaced from the locality of attachment of said other end of said first elongate flexible means to said swing frame means, whereby rectilinear movement of said portion having a cylindrical bore in one direction causes one of said elongate flexible means to rotate said swing frame means in one direction and retains the tautness of the other elongate flexible means in the other direction and the tautness of both of said flexible means is thereby maintained at all times.

7. Apparatus according to claim 1 which also comprises means on the swing frame means associated with one end of at least one of said flexible means for adjusting the tautness of said one flexible means.

8. Apparatus according to claim 1 which also comprises means for adjustably securing at least one of said elongate flexible means to said portion having a cylindrical bore, whereby the tautness of said flexible means may be adjusted.

9. Apparatus according to claim 1 wherein the guide means for said portion having a cylindrical bore comprise guide means on the said portion having a cylindrical bore which coact with guide means on the main frame.

10. Apparatus according to claim 9 wherein the guide means on the said portion having a cylindrical bore is positioned at an external portion of the said portion having a cylindrical bore, whereby axial movements of the said portion having a cylindrical bore and the attached elongate flexible means are limited.

11. Apparatus according to claim I wherein the rod portion of the ram of the hydraulic motor means comprises means for adjusting its length.

12. Apparatus according to claim 1 which comprises means for adjusting the spacing between at least one end of the rod portion of the ram of the hydraulic motor means and the main frame.

13. Apparatus according to claim I wherein one end of the first elongate flexible means is attached adjacent to one end of said portion having a cylindrical bore and the other end of said first elongate flexible means is attached to a side of the swing frame means which is remote from said one end of the said portion having a cylindrical bore, one end of the second elongate flexible means is attached adjacent to the other end of the said portion having a cylindrical bore and the other end of said second elongate flexible means is attached to the opposite side of said swing frame means, whereby the swing frame means is swung in a direction opposite to the direction of rectilinear movement of the said portion having a cylindrical bore, thereby to provide a compact device when viewed from the top. 

1. In swing mechanism for an earth-moving apparatus comprising, a main frame adapted to be carried by a vehicle, swing frame means, and substantially vertical pivot means connecting said main frame and said swing frame means for swinging movement of said swing frame means about said substantialLy vertical pivot means, the improvement comprising, a single, double-acting ram-type hydraulic motor means, comprising a portion having a cylindrical bore and a piston rod having at least one end supported by at least one laterally spaced member of said main frame, a pair of elongate flexible means, one end of each of said flexible means being attached to said swing frame means, the other end of one of said flexible means being attached to said portion having a cylindrical bore adjacent to one end thereof and the other end of the other of said flexible means being attached to said portion having a cylindrical bore adjacent to the end thereof, means on the main frame and on said portion having a cylindrical bore for guiding said portion having a cylindrical bore and at least portions of said flexible means for rectilinear movement, and said swing mechanism being free from any sheaves for coaction with said elongate flexible means, whereby rectilinear movement of said portion having a cylindrical bore by said motor means causes said swing frame means to swing about said substantially vertical pivot means and longitudinal movement of both of said elongate flexible means.
 2. Apparatus according to claim 1 which also comprises boom means having one end pivotally attached to said swing frame means permitting movement of said boom in a substantially vertical plane and wherein said means for guiding said portion having a cylindrical bore guides its rectilinear movement in a direction which is substantially normal to the longitudinal centerline of the boom when the swing frame means is substantially at the center of its substantially horizontal swinging movement and the apparatus is viewed from the top.
 3. Apparatus according to claim 2 wherein said swing frame means comprises a generally cylindrical member which is substantially coaxial with said vertical pivot means, and when said swing frame means is substantially at the center of its swing and the apparatus is viewed from the top, each of said elongate flexible means passes around an arcuate peripheral face of the generally cylindrical member across a plane through the longitudinal centerline of the boom which is substantially normal to the longitudinal centerline of said portion having a cylindrical bore, and thence substantially parallel to said latter longitudinal centerline to the locality of attachment of its ends to said portion having a cylindrical bore, whereby during each unit of rectilinear movement of said portion having a cylindrical bore, a substantially equal unit of one of said elongate flexible means is unwound from the generally cylindrical member and a substantially equal unit of the other of said elongate flexible means is wound upon the generally cylindrical member.
 4. Apparatus according to claim 2 wherein one end of the first elongate flexible means is attached to a first locality of said portion having a cylindrical bore and one end of the second elongate flexible means is attached to a second locality of said portion having a cylindrical bore which is spaced from said first locality and both said localities of attachment are located between the longitudinal centerline of said portion having a cylindrical bore and a plane through the axis of said vertical pivot means which is substantially normal to the longitudinal centerline of the boom when the apparatus is viewed from the top and thw swing frame means is substantially at the center of its swing, whereby axial and lineal loads of the flexible means are taken by said means for guiding said portion having a cylindrical bore.
 5. Apparatus according to claim 2 wherein said swing frame means comprises a generally cylindrical member which is substantially coaxial with said vertical pivot means, and when said swing frame means is substantially at the center of its swing and the apparatus is viewed from the top, each of said elongate flexible means passes around an arcuate peripheral face of the generally cylindrical meMber across a plane through the longitudinal centerline of the boom which is substantially normal to the longitudinal centerline of said portion having a cylindrical bore, whereby when the swing frame and boom have been swung to the full extent of their swing in one direction, the portion of one elongate flexible means which engages said arcuate peripheral face is greater than the length of the remainder of said one elongate flexible means.
 6. Apparatus according to claim 1 wherein one end of the first elongate flexible means is attached to a first locality of said portion having a cylindrical bore and one end of the second elongate flexible means is attached to a second locality of said portion having a cylindrical bore which is spaced from said first locality, the other end of said first elongate flexible means being attached to a first locality of said swing frame means and the other end of said second elongate flexible means being attached to a second locality of said swing frame means which is spaced from the locality of attachment of said other end of said first elongate flexible means to said swing frame means, whereby rectilinear movement of said portion having a cylindrical bore in one direction causes one of said elongate flexible means to rotate said swing frame means in one direction and retains the tautness of the other elongate flexible means in the other direction and the tautness of both of said flexible means is thereby maintained at all times.
 7. Apparatus according to claim 1 which also comprises means on the swing frame means associated with one end of at least one of said flexible means for adjusting the tautness of said one flexible means.
 8. Apparatus according to claim 1 which also comprises means for adjustably securing at least one of said elongate flexible means to said portion having a cylindrical bore, whereby the tautness of said flexible means may be adjusted.
 9. Apparatus according to claim 1 wherein the guide means for said portion having a cylindrical bore comprise guide means on the said portion having a cylindrical bore which coact with guide means on the main frame.
 10. Apparatus according to claim 9 wherein the guide means on the said portion having a cylindrical bore is positioned at an external portion of the said portion having a cylindrical bore, whereby axial movements of the said portion having a cylindrical bore and the attached elongate flexible means are limited.
 11. Apparatus according to claim 1 wherein the rod portion of the ram of the hydraulic motor means comprises means for adjusting its length.
 12. Apparatus according to claim 1 which comprises means for adjusting the spacing between at least one end of the rod portion of the ram of the hydraulic motor means and the main frame.
 13. Apparatus according to claim 1 wherein one end of the first elongate flexible means is attached adjacent to one end of said portion having a cylindrical bore and the other end of said first elongate flexible means is attached to a side of the swing frame means which is remote from said one end of the said portion having a cylindrical bore, one end of the second elongate flexible means is attached adjacent to the other end of the said portion having a cylindrical bore and the other end of said second elongate flexible means is attached to the opposite side of said swing frame means, whereby the swing frame means is swung in a direction opposite to the direction of rectilinear movement of the said portion having a cylindrical bore, thereby to provide a compact device when viewed from the top. 